The subject matter disclosed herein relates to the art of turbomachines and, more particularly, to an injection nozzle for a turbomachine.
In general, gas turbine engines combust a fuel/air mixture that releases heat energy to form a high temperature gas stream. The high temperature gas stream is channeled to a turbine via a hot gas path. The turbine converts thermal energy from the high temperature gas stream to mechanical energy that rotates a turbine shaft. The turbine may be used in a variety of applications, such as for providing power to a pump or an electrical generator.
In a gas turbine, engine efficiency increases as combustion gas stream temperatures increase. Unfortunately, higher gas stream temperatures produce higher levels of nitrogen oxide (NOx), an emission that is subject to both federal and state regulation. Therefore, there exists a careful balancing act between operating gas turbines in an efficient range, while also ensuring that the output of NOx remains below mandated levels. One method of achieving low NOx levels is to ensure good mixing of fuel and air prior to combustion. Moreover, when using pure H2 or high H2 combustion, fuel jet penetration is not sufficient to mix with available air. As such fuel will flow through a boundary layer in a premixer tube portion of the injector. This fuel behavior results in a flashback condition that limits an overall operational range of the turbomachine.